列表创建在 Ansible 中为 false 时添加 'undefined' 条目

Question

我有以下基本有效的剧本 -

vars:
ansible_network_os: ios
IOSserials: []

  tasks:

- name: Get all facts from ios devices
  register: all_facts
  ios_facts:
    gather_subset: hardware

- name: Create list Serials
  set_fact:
    IOSserials: "{{IOSserials|default([]) +  [{ 'name': all_facts.ansible_facts.ansible_net_hostname, 'IOS_serial': all_facts.ansible_facts.ansible_net_serialnum }] }}"
  when: hostvars[inventory_hostname].serial !=  all_facts.ansible_facts.ansible_net_serialnum 

- name: Display list
  debug:
    msg: "These switches have a difference in serial number {{ ansible_play_hosts_all|map('extract', hostvars, 'IOSserials')|list }}"
  run_once: true

结果如下（我在开关中有一个 'not equal' 场景）：

TASK [Create list Serials] *****************************************************
skipping: [lab3650s1] => {"changed": false, "skip_reason": "Conditional result was False"}
skipping: [lab4500s1] => {"changed": false, "skip_reason": "Conditional result was False"}
ok: [lab3650s2] => 
    {"ansible_facts": {"IOSserials": [{"IOS_serial": "FDO201XXXXD", "name": "lab3650s2"}]}, "changed": false}

TASK [Display list] ************************************************************
ok: [lab3650s1] => {
    "msg": "These switches have a difference in serial number [Undefined, [{'name': 'lab3650s2', 'IOS_serial': 'FDO201XXXXD'}], Undefined]"
}

PLAY RECAP *********************************************************************
lab3650s1 : ok=2    changed=0    unreachable=0    failed=0    skipped=1    rescued=0    ignored=0   
lab3650s2 : ok=2    changed=0    unreachable=0    failed=0    skipped=0    rescued=0    ignored=0   
lab4500s1 : ok=1    changed=0    unreachable=0    failed=0    skipped=1    rescued=0    ignored=0

我不想要输出列表中的 'undefined' 条目，我还想了解为什么 Ansible 在跳过这些条目的 set_fact 时将其插入列表中。

Answer 1

那个 map 管道缺少 select 可以过滤掉那些 extract 没有产生有意义的值的管道；你可以看到它很容易重现：

- set_fact:
    thingy:
      one:
        apple: is red
      two:
        banana: is yellow
      three:
        apple: is green
- debug:
    msg: >
     {{ ["one", "two", "three"] | map("extract", thingy, "banana") | list }}
- debug:
    msg: >
     {{ ["one", "two", "three"]
     | map("extract", thingy, "banana")
     | select
     | list }}

列表创建在 Ansible 中为 false 时添加 'undefined' 条目

List creation addding 'undefined' entries when false in Ansible

list

undefined

ansible